多肽掺杂的聚苯胺与氧化石墨烯共价复合物的合成与表征

利用含有氨基和羧基官能团的多肽原位掺杂聚苯胺,在聚苯胺的表面引入游离的氨基,再通过氨基与氧化石墨烯表面羧基的酰胺化反应使聚苯胺与氧化石墨烯通过共价键结合形成共价复合物。利用傅里叶变换红外光谱仪、热重分析仪、场发射扫描电子显微镜、透射电子显微镜和高倍透射电子显微镜对共价复合物进行了表征。研究结果表明,共价键能够提高复合物的稳定性,共价键还能够影响其超分子结构。     

氧化还原法制备石墨烯及其表征

采用改进的Hummers法氧化处理石墨粉制得氧化石墨,利用超声波作用将氧化石墨剥离,得到均匀分散的氧化石墨烯胶状悬浮液,然后在水合肼的还原作用下得到石墨烯。采用SEM、XRD以及Raman光谱对样品进行了形貌、结构以及谱学的表征分析。考察了还原过程中温度对还原效果的影响,以及中性条件下、碱性条件下水合肼用量对还原效果的影响。     

氧化石墨烯及其与聚合物的复合

石墨烯是单原子厚度的二维碳原子晶体,也是性能优异的新型纳米复合填料.近三年来,石墨烯从概念上的二维材料变成现实材料,在化学和物理学界均引起轰动.通过述评氧化石墨及氧化石墨烯的制备、结构、改性及其与聚合物的复合,展望了石墨烯及其复合材料的研究前景,认为通过机械剥离氧化石墨可规模化制备氧化石墨烯,进一步将其化学改性并制备复合材料已取得较大进展,这一途径被认为足石墨烯规模化应用的战略起点.     

石墨烯接枝聚吡咯复合物的原位合成及其电容特性研究

采用化学接枝法原位合成了石墨烯接枝聚吡咯复合物, 对复合物的结构、形貌、导电率以及比电容值进行了测试和表征。结果表明制备的石墨烯接枝聚吡咯复合物中, 石墨烯与吡咯单体间产生了紧密的化学键结合, 吡咯在石墨烯层片上均匀分布, 石墨烯片层间的吡咯大量成链并与石墨烯层片相互连接, 测得复合物的电导率为3.32 S/cm, 比电容值可以达到284 F/g, 相比于纯聚吡咯的186 F/g的比电容值提高了52%, 具有优异的电容特性。     

氧化石墨烯原位合成VC及其负载Pt氧还原催化性能

为了开发高性能燃料电池催化剂,研究以氧化石墨烯为载体和碳源合成VC及其负载Pt催化剂的合成、结构和催化氧还原性能。结果表明:氧化石墨烯可以作为碳源在氢气气氛下与V_2O_3原位合成VC,同时在氨气气氛下热处理还可以对其进行氮的掺杂,氮掺杂将其催化氧还原的起始电势提高了0.15V。石墨烯与氮掺杂VC负载Pt具有良好的催化氧还原性能,其峰值电流、起始电势以及循环寿命都超过了传统的Pt-C催化剂。     

Co3O4/还原氧化石墨烯复合物的合成及其结构与性能表征

用回流法以及后续热处理过程合成了Co3O4/还原氧化石墨烯(rGO)复合物。并对样品的成分、形貌、结构以及电化学性能进行了表征与测试。研究结果表明,当Co3O4与rGO的质量比为87∶13时,复合物比电容达到760F.g-1,并且此复合物表现出较好的循环稳定性。     

石墨烯及Ag/石墨烯纳米复合材料的原位合成

选择改进的H ummer方法制备氧化石墨烯;采用硼氢化钠和柠檬酸钠相结合的方法还原氧化石墨制备石墨烯及Ag/石墨烯纳米复合材料,采用拉曼光谱、TEM、SEM、UV-Vis、XRD、FTIR等多种测试手段对其表征,发现硼氢化钠可以还原氧化石墨烯中的边缘缺陷,柠檬酸钠可以剥离氧化石墨烯片层并使银纳米颗粒附着在石墨烯片层上,石墨烯层数较少且随着反应时间的延长,银纳米颗粒的尺寸也会逐渐增大.     

氧化石墨烯的制备及其负载抗感染药物的研究

石墨烯是由碳原子以sp2杂化排列形成的,具有单原子层结构的新型二维原子晶体。迄今为止,石墨烯的量子物理特性及其在纳米电子元件、透明导体、纳米复合材料等方面的潜在应用已被人们研究,但其在生物医药领域的应用却很少有报道。文章制备出功能化的氧化石墨烯具有良好的水溶性和稳定性,通过研究氧化石墨烯与抗感染药物-哌拉西林钠他唑巴坦钠的作用机制,探索其在生物医药领域的应用。     

还原氧化石墨烯/Al-Ni层状双氢氧化物复合物的制备及其电化学电容行为

以硝酸镍和硝酸铝为原料,尿素作为还原剂和沉淀剂,通过水热法一步合成了不同配比的还原氧化石墨烯/Al-Ni层状双氢氧化物复合物(rGO/LDH)。用X射线衍射(XRD),红外光谱(FT-IR),拉曼光谱(Raman)和场发射扫描电镜(FESEM)对其结构和形貌进行物理表征。采用循环伏安,恒电流充放电等电化学方法系统研究了所制备样品的电化学性能。结果表明,当Al-Ni层状双氢氧化物(LDH)与还原氧化石墨烯(rGO)的配比为96.2∶3.8时,复合物具有最佳的电容性能。在电流密度为1A·g-1时,其比电容高达918.4F·g-1,远高于纯Al-Ni层状双氢氧化物(LDH)的比电容(732F·g-1)。     

氧化石墨烯制备石墨烯的研究进展

近年来,石墨烯已成为世界各国学者研究的热点。由石墨粉先制备氧化石墨烯进而制备石墨烯成为了石墨烯最重要的制备方法。本文综述了氧化石墨烯制备石墨烯的主要方法:化学法、热法、微波法、电化学法、水热法、碱法等,并对各方法的优缺点进行了阐述,最后对石墨烯的未来进行了展望。     

Appropriate conditions for preparing few-layered graphene oxide and reduced graphene oxide

Oxidation time and exfoliated conditions of graphite oxides (GOs) were investigated to prepare few–layer graphene oxide and reduced graphene oxide via a modified Hummers approach. Different oxidative degree of GOs was prepared by changing oxidation time, and the effects of oxidative degree of GOs in different oxidation time were studied by XRD, FT-IR. Afterwards, highly oxidized GOs were used as precursor to prepare graphene oxide and reduced graphene oxide by ultrasonic dispersion method and thermal expansion method. The exfoliated conditions (ultrasonic power and ultrasonic time, thermal exfoliated temperature) were investigated to prepare few-layered graphene oxide and reduced graphene oxide.     

Fabrication of graphene oxide/bentonite composites with excellent adsorption performances for toluidine blue removal from aqueous solution

The graphene oxide/bentonite (BG) composites are prepared through graphene oxide (GO) nanosheets successfully intercalated into acid-treated bentonite interlayer and deposited onto external surface. The BG composites exhibit a higher uptake capacity of toluidine blue (TB) dye from water solutions than normal bentonite owing to the synergistic effect between bentonite and GO. The as-prepared composites are characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and N₂-sorption analysis. The process parameters affecting the adsorption behaviors such as initial pH, temperature, contact time and initial concentration of dye are systematically investigated. The Langmuir isotherm model fit well with the equilibrium adsorption isotherm data and the maximum adsorption capacity is 458.7?mg·g^?1 at pH 8 for BG composites modified using 1% GO. The pseudo-second-order kinetic model well describes the adsorption process of TB onto BG composites. The TB adsorption on BG composites is mainly attributed to ion exchange, electrostatic interaction and intermolecular interactions. The outstanding adsorption performances of composites for the removal of TB dye from water demonstrate its significant potential for environmental applications.     

Synthesis of manganese dioxide/reduced graphene oxide composites with excellent electrocatalytic activity toward reduction of oxygen

MnO₂/reduced graphene oxide(RGO) composites were synthesized by a facile and effective polymer-assisted chemical reduction method. The synthetic MnO₂/RGO composites have a uniform surface distribution and large coverage of MnO₂ nanoparticles onto graphene, which were characterized with scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and cyclic voltammetry. The synthetic MnO₂/RGO composites were studied with respect to its electrocatalytic activity toward the reduction of oxygen in alkaline media and were found to possess a good electrocatalytic activity toward the four-electron reduction of oxygen.     

乙二胺和己二胺氨基功能化氧化石墨烯(英文)

采用了一种通过采用乙二胺和己二胺接枝改性制备氨基功能化石墨烯的高效、经济的方法。结果表明,该方法可对氧化石墨烯进行有效的氨基化,且官能化程度较高,每9～10个碳原子中就有一个参与氨基化反应;随着二元胺烷基链长度的增长,氨基功能化氧化石墨烯的的热稳定性得到明显提高,但在N,N-二甲基甲酰胺溶剂中的分散性却会变差。     

Solvent exfoliated graphene for reinforcement of PMMA composites prepared by in situ polymerization

Graphene (GP)-based polymer nanocomposites have attracted considerable scientific attention due to its pronounced improvement in mechanical, thermal and electrical properties compared with pure polymers. However, the preparation of well-dispersed and high-quality GP reinforced polymer composites remains a challenge. In this paper, a simple and facile approach for preparation of poly(methyl methacrylate) (PMMA) functionalized GP (GPMMA) via in situ free radical polymerization is reported. Fourier transform infrared (FTIR), X-ray photoelectron spectra (XPS), Raman, transmission electron microscope (TEM) and thermogravimetric analysis (TGA) are used to confirm the successful grafting of PMMA chains onto the GP sheets. Composite films are prepared by incorporating different amounts of GPMMA into the PMMA matrix through solution-casting method. Compared with pure PMMA, PMMA/GPMMA composites show simultaneously improved Young's modulus, tensile stress, elongation at break and thermal stability by addition of only 0.5 wt% GPMMA. The excellent reinforcement is attributed to good dispersion of high-quality GPMMA and strong interfacial adhesion between GPMMA and PMMA matrix as evidenced by scanning electron microscope (SEM) images of the fracture surfaces. Consequently, this simple protocol has great potential in the preparation of various high-performance polymer composites.     

Reduced graphene oxide/metal oxide nanoparticles composite membranes for highly efficient molecular separation

Graphene oxide(GO) membranes play an important role in various nanofiltration applications including desalination, water purification, gas separation, and pervaporation. However, it is still very challenging to achieve both high separation efficiency and good water permeance at the same time. Here, we synthesized two kinds of GO-based composite membranes i.e. reduced GO(rGO)@MoO_2 and rGO@WO_3 by in-situ growth of metal nanoparticles on the surface of GO sheets. They show a high separation efficiency of ～100% for various organic dyes such as rhodamine B, methylene blue and evans blue, along with a water permeance over 125 Lm~(-2) h~(-1) bar~(-1). The high water permeance and rejection efficiency open up the possibility for the real applications of our GO composite membranes in water purification and wastewater treatment. Furthermore, this composite strategy can be readily extended to the fabrication of other ultrathin molecular sieving membranes for a wide range of molecular separation applications.     

Unusual toughening effect of graphene oxide on the graphene oxide/nylon 11 composites prepared by in situ melt polycondensation

Graphene oxide/nylon 11 composites were prepared by in situ melt polycondensation. These composites displayed better mechanical properties including stiffness and toughness than the pure nylon 11 matrix. The enhanced toughness was ascribed to the change of crystal form of nylon 11, namely the triclinic α crystal form to the pseudo-hexagonal δ′ crystal form transition trend with the incorporation of GO. Scanning electron microscopy and transmission electron microscopy images showed that GO bundles and stacks with an average thickness of 20 nm are homogeneously dispersed over the nylon 11 matrix with almost no large agglomerates.     

Synthesis of carbon-mineral composites and graphene

Abstract

С/Al₂O₃ and C/MgO carbon-mineral composites were synthesized by propane decomposition over Al₂O₃ at 600–650?°C and MgO carbonization in 1,3-butadiene at 600?°C. The synthesized carbon-mineral composites were studied by EPR, XRD and transmission electron microscopy. It was found that a mosaic structure of carbon clusters was formed on the internal surface of the oxides and gradually grew until it covered its whole surface. A method for synthesis of graphene materials by using MgO as a template followed by its dissolution in hydrochloric acid was suggested. A maximum was observed on the dependence of the graphene surface area on the carbon concentration in the composites. The highest specific surface area of the synthesized graphene about 1800–1900?m²/g was observed for the samples obtained from C-MgO composites containing 8–10?wt.% C.     

Synthesis and characterization of N-[4-(chlorocarbonyl)phenyl]maleimide functionalized graphene oxide and reduced graphene oxide

Functionalization of graphene oxide leads improvement in thermal stability and flame retardancy. Acid chloride terminated N-[4-(chlorocarbonyl)phenyl]maleimide (Cl-CPMI) was synthesized to decorate hydroxyl group in graphene oxide (GEO) and glycine-reduced GEO (RGEO). Structural characterization of the materials was performed using FTIR, ¹³C NMR and Raman spectroscopic methods. Interlayer distance and surface morphology were also studied using X-ray diffraction and scanning electron microscopic methods, respectively. The absence of the band for C-Cl and shortening of the O-H band in the FTIR and peak in ¹³C NMR spectra confirm the functionalization of alcoholic group on the graphitic plane with Cl-CPMI. The ratio, I_D/I_G computed from Raman study, the nature of XRD pattern and interlayer distance between the adjacent graphitic layers were not affected by the functionalization of GEO and RGEO using Cl-CPMI. The tagging of maleimide unit with the graphitic plane was also confirmed by the cloudy appearance in the SEM images.     

Reduced graphene oxide supersonically sprayed on wearable fabric and decorated with iron oxide for supercapacitor applications

We demonstrate the fabrication of wearable supercapacitor electrodes.The electrodes were applied to wearable fabric by supersonically spraying the fabric with reduced graphene oxide(rGO)followed by decoration with iron oxide(Fe2O3)nanoparticles via a hydrothermal process.The integration of iron oxide with rGO flakes on wearable fabric demonstrates immense potential for applications in high-energy-storage devices.The synergetic impact of the intermingled rGO flakes and Fe2O3 nanoparticles enhances the charge transport within the composite electrode,ultimately improving the overall electrochemical performance.Taking advantage of the porous nature of the fabric,electrolyte diffusion into the active rGO and Fe2O3 materials was significantly enhanced and subsequently increased the electrochemical interfacial activities.The effect of the Fe2O3 concentration on the overall electrochemical performance was investigated.The optimal composition yields a specific capacitance of 360 F g-1 at a current density of 1A g-1 with a capacitance retention rate of 89％after 8500 galvanostatic cycles,confirming the long-term stability of the Fe2O3/rGO fabric electrode.